Evaluation of the cohesive bond strength of bitumen and mastics

The evaluation of fundamental mechanical properties of bitumen is vital to construct long-term performing pavements. This research evaluates cohesive bond strength of bitumen and mastics using compression pull-off test (CPOT). The results show problems in the common interpretation of load-displacement curves. A discussion is made on fibrillary nucleation in binder. The curing for 24 h is sufficient for the development of the cohesive bond. Furthermore, longer conditioning is needed to evaluate the moisture damage using aluminium plates. Bitumen source, grade, filler content, and loading rate affect the pull-off strength (POS). Ageing increases POS and shifts the failure mode towards brittle. The type of filler does not affect POS after short-term ageing. The moisture conditioning reduces the POS and results in a mixed to adhesive failure with increased variability in results. The aggregate plates are necessary for detailed moisture damage evaluation. The use of re-used aggregate substrate is found to be ineffective.